Answer:
30 hours
Step-by-step explanation:
The equation we use is 1/15 + 1/x = 1/10. X being the amount of time it takes Ian alone. X works out to 30 hours which is the answer
18.84
Since the formula of circumference is C = 2 pi r or C = pi times diameter, you can conclude that the circumference is 18.84.
Assuming that pi is 3.14 in this case rather than the full pi or just in terms of pi.
Hope this helps!
